Automatic telephone-exchange system.



F. N. REEVES & A. E. LUNDELL.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAY 10.. I913.

Patented May 29, 1917.

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y Ax/y F. N: REEVES & A. E. LUNDELL. AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAY 10. 1913.

1,227,932. Patented May 29,1917.

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F. N. REEVES & A. E. LUNDELL'. AUTOMATIC TELEPHONE EXCHANGE SYSTEM! APPLICATION FILED MAYIO. 191'3.

Patented May 29, 191?.

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UNiTED s'ra'rss FRANK N. REEVES, OF 'NEWARK, NEW. JERS BY, AND ALBEN E. LUNDELL, osnnw Your,

N. Y., ASSIGNOBJS, BY MESNE ASSIGNMENTS, IO "WESTERN'ELECTRIC COMPANY, INCORPORATED, .A CORPORATION OF EEW YORK.

Specification of Letters Patent.

Patented May as, ism.

Application filed May 10, 1913. Serial No. 766,903.

To all whom it may concern:

Be it known that we, FRANK N. Rnnvns and ALBEN E. LUNDELL, citizens of the United States, residing at Newark, in the county of Essex and State of New Jersey, and at New York, in the county and State of New York, respectively, have invented a certain new and useful Improvement in Automatic Telephone-Exchange Systems, of

which the following is a full, clear, concise,

satelliteshaving a capacity of ten thousand lines, making the capacity of the whole systein one hundred thousand lines. The capacii y of the satellites may be for instance one thousand subscribers lines .each, although the number obviously mayvary according to What therequirements l'nay be in practice. The subscribers lines may terminate either in a "satellite or directly in a The object of this invention is to economize 1n the use of trunk lines between the satellites and main offices Without the necessity of variable manipulation of the sub-' scribers? calling devices to dlscriminate between calls local to a satellite and calls reun-mg connection through a mam office.

To this end automatic discriminating means satellite with the calling.

have, for example,

The characteristic feature of this invention is, therefore, that it provides in an automatic satellite exchange system, means whereby a subscriber connected to'a satellite may be called without any discriminating act at the calling device, wherever located in the exchange, to direct the connection and without extending the talking connection through an interoifice trunk where the calling and calledsubscribers lines terminate in the same satellite.

Each of the subscribers lines at a satellite is associated with a pair of trunk finder devices, one only of which is used in extending a call to a subscriber external to. the satellite, both being used in making connection to called subscribers in the same In addition to the trunk finder just mentioned, each satellite is provided with a group of hundreds selectors and connectors through which the satellite subscribers are reached when a call originates at the same satellite therewith and also a group of connectors through which the subscribers at the satellite are reached when the call originates external to the satellite.

The invention will stood by reference to the accompanying drawings wherein- Figure l is a diagrammatic illustration of the multi-oilic satellite exchange system embodying the invention, and Figs. 2, 3 and be more readily under- 4: when placed together with Fig. 3 above represents a pair of trunk finders such as is associated with each subscribers line atthe satellite.

Fig. 3 represents a first selector at the main exchange and a trunk finder associated therewith, and

Fig. 4 represents a'hundreds selector and a connectorat the satellite and 2). called subscribersline' and substation apparatus,

In Fig. la main office connected by trunk lines 100 to other main ofhces A, B, C and E, it being understood that similar trunk lines would extend in such an exchange from each of said 'mam ofiices to each other main oiiice.

1 of the drawings, 1) represents v Associated with the main cities A are satellites, A, 1 and A and subscribers stations a, (If, and similarly associated with the main exchange 13 are satellites B, B and B and subscribers stations 7), I), and the other main offices may have satellites O, C and C E, E and E, etc, the satellites being represented by the circles and the subscribers stations by the small squares.

Associated with the main ollice I), the confines of which are indicated by the do"- ted rectangle, are the satellites I) and D and the subscribers stations fl and d which are located at the satellite 1) and other subscribers stations (Z and 5? connected directly to the main office. .The main ollice 1) may include a number of series of switching mechanisms represented therein by a first selector 101 and a second selector 102, from which trunk lines would extend to the third selectors of other main exchanges and also a third selector 103 to which trunks from other main exchanges would extend and a final connector 10st through 'which sub scribcrs, local to the main exchange 1), would be reached by calling subscribers at other main exchanges. In addition to these series of switching devices, other series of switching devices are provided including the first selectors 101, trunk finders 105,

hundreds selectors 106 and final connectors 10?, through which all the subscribers at the main exchange D would be reached by calling subscribers at thesatellite 1). Subscribers at the satellite 1) would be reached by subscribers local to the main exchange D and by all subscribers at other main err-- changes through a trunk line similar to the trunk line 114: leading from said third selector to the satellite D A call originating at I) would be extended to a subscriber at D by way of the first selector 101, trunk finder 105, third selector 106, a trunk line leading from 106 to D and a final selector (corresponding to 115 'atD') at the satellite D While most of the switching devices are illustrated and have been referred toin the singular herein, it is obviously to be understood that a plurality or group of these switches will be provided unless otherwise described.

The apparatus at a satellite such as I), for

. instance, may include line switches 108 and 109, selectors 403, and connectors L10 previously referred to. The arrangement of the apparatus thus diagraminatically illustrated in Fig. 1 is such. that the subscriber at station d, for exai'nple, may obtain a connection to the subscriber at station (1 over a local circuit such as 112 which is wholly within the satellite, or he may ob tain a connection to any other subscriber ot' the exchange systcm'whose line does not tcrniii'iatc at the satellite 1) through a trunk line; such as 113 leading to the main office D, from whence the connection may be extended in the usual manner according to the particular location of the subscriber wanted. If any subscriber other than those connected to the satellite 1) desires connection witha subscriber at this satellite, the circuit would be completed by way of selectors such as 101, 102 and 103 (variously positioned according to the location of the calling subscriber) through a trunk line as 114: to a final connector 115 at the satellite D.

At this point it is sufiicient to say that if a subscriber at rZ sends calling impulses in correspondence to the number of some other station at the same satellite therewith, the trunk finder 108 will first pick a trunk 113 leading to the main oli'ice D and if by means of vertical impulses the brushes of the selected selector 101 are brought to a certain level or group of contacts, the circuits at said switch will be so altered that the ensuing movement, instead of being the usual automatic trunk hunting operation, will be a directive movement and. it the next series of impulses is such as to place the brushes of said selector 101 on a particular group of contacts individual to the satellite D',a loop circuit will be completed, whereby the calling line will be automatically disconnected from the trunk finder 108 and connected to the trunk finder 105) which will automatically pick a connecting circuit as 112 lead ing to a hundreds selector 403. The succeeding series of impulses will now act in the usual manner to first pick a final connector of a certain group and then direct the brushes of this final connector to the terminals of the wanted subscriber.

Referring now to Figs. 2, 3 and 4 wherein the circuits and apparatus required for the establishment of a connection between a subscriber at al Fig. 2 with a subscriber at d Fig/l are diagrammatically illustrated, each subscribers line, such as line 200, 201 of the calling station cl, is provided at the substationl. with the usual telephone apparatus and a controlling device or interrupter 202, the purpose of which is to deliver the ope'rating impulses by interrupting the circuit at the substation, and at the satellite exchange with a pair of trunk finders '108 and 10.9. The sides 200, 201 of the line exi tend uninterruptedly to the switch spring 205 and contact of spring 206 respective] y of trunk finder 100. The side 200 of the line also extends through armature 207 and back contact of magnet 212, wire 214, back contact and armature 200 of magnet 212, wind-' ing 211 of magnet 212 and battery 213 to ground. The side 201' of the line correspondingly extends through armature 20R and back contact of clectromagnet 212, wire 215, back contact 216 and armature 210 to ground. Continuations 0f the conductors 214 and. 215 also extend. to switch spring- 229 and contact of spring 230, respectively, at trunk finder S.

In addition to the branches from the sidesm suitable mechanism, that shown diagram mati rally in the drmvings being sin'iilar to the agtuoaratus disclosed in British Patent i No, 26,301 of 1.966. Fer more specific description oi the selector and connector referonce is made/to United States .Patcn'ts Nos.

815,321 and 815,176, respectively. The plunger 217 of the trunk finder, as well understood, always stands before a'set of springs associated with an idle connecting circuit and upon sufficient energization of the electromagnet 2l2tl1is plunger will be drawn forward, forcing the insulating" ball 218 thereof between the innermost springs of said set, whereby each of the four springs of the set is forced outwardly into engagement with its cooperating contact. The lead 219 associated with the innermost upper contact spring of the switch extends to the master switch bank whercl'iy, through the actuation of well known means, all the idle plungers of the group are nioi ed to the next idle position. Normally, current is supplied to the lead 220, but during the interval when the plungcrs are in transit from one positionof rest to the next, this lead is interrupted, for

instance at contact 222, so that no line finder mechanism can be actuated during this interval. As hcreinbefore stated, calls local to the satellite will'be extended by the trunk 40 finder 109 by means of a third selector 403 and a connector 4-10 to the called subscriber. As such apparatus is well known in the art, it need not be fully described here. The selector may be of the two movement type wherein a series of steps is taken to select the desired group of connectors, and then auton'iatically hunts for an idle-connector of the group. Likewise the connector may be of the two IXIOVGIl'lGnt type in which the brushes so are first stepped toa certain group of contacts and then are moved to the terminals of the wanted subscribers line. i In Fig. 3 is shown a first selector of any suitable type and a trunk finder associated therewith, the

function for which willhereinafter appear.

Tn Fig. 4 is shown the talking circuit conductor of the apparatus including" the main Swiirh contacts 4 5. 106 of the Selector 403,

and 4 0?. ill C ol' the connector-410. also con- .50 densers 4-H!) and ll 1, im icdaucc coil role 5 as battery 4121- Associated with the selector and connector switches 402-, and 41o lhurc would preferably be local test and holding contacts 417 and 418 .respcctivcly. The brush of the latter is adapted to be connected to ground at 419 when the conuccior is brought to rest on the terminals of a culled linepthe object of thisbeing to create a busy :testcondition for other connector switches. @f'jItLWlll be understood that the line of the called subscriber will have associated with it trunk finders such as shown 1n assocmtion 'with the-line of the calling substation d and that the connections to such apparatus will be made by the conductors 4.21 and 422 corresponding to the conductors 200 and 201 respectively of the calling subscribers line. As further description of the apparatus employed is not believed to be necessary, the

operation of the system will now be described.

"Let it be assumed that the subscriber at station d is calling for the subscriber at station (Z these two stations being connected to the same satellite, and let it be further assumed that this satellite contains a group of subscribers lines numbered from 99-000 to 99999, and that the number of the calling subscriber is 99321. The calling subscriber at station d removes his receiver from the hook, thereby closing the line circuit through the winding 211 of magnet 212, the current flowing over the followingpath: from the live side of the battery 213, winding 211 of magnet 212, armature 209 and contact, wire 214, armature 207 and back contact of electromagnet 212, side 200 of the line, substation apparatus, side 201 of the line, armature 208' and back contact,

wire 2155, contact 216 and armature 210to ground. This partially energizes the electromagnet 212 and the armature 221 alone is attracted. The attraction of this armature closes the circuit from battery through the normally closed contact 222, wire 220, windings 223, 22%, contact and armature 221, contact 225 and armature 210 to ground. This results in the attraction of left armatures 209, 210 and 226 of electromagnet. 212, and also the attractionof the right armature 227 which actuates the plunger 217 to force the insulating knot 218- between the innermost contact; springs, thus closing all the contacts now associated with this plunger. The armature 227 in pulling up engaged the contact 228, thus completing a short circuit about the winding 223, whereby the electromagnet 212 is made slow to release. It will be noted that the attraction of armature 210 has broken the original energizing circuit for the windings 223 and 224, but on account of the short circulting of the winding 223, the armature 227 is re tained attracted until a holding circuit is completed. When the plunger entered the set of springs, the sides of the subscriberls line were extended by springs 229 and 230 J and cooperating contacts through the wires live pole of battery 302, upper winding of relay 301, contact 303, side switch wiper 304, wire 231, contact and spring 229, wire 214, contact and armature 207, side 200 of the line, substation apparatus, side 201 of the line, armature 208 and contact, wire 215, spring 230 and contact, wire 232, Side switch wiper 305, contact 306, through the lower wi ding of relay 301 to ground. Upon the energization of relay 301, circuit is completed for relay 307 from the live pole of grounded battery through winding of 307, front contact and armature of 301 to ground, whereupon relay 307 attracts both armatures. The upper armature completes a holding circuit for the electromagnet 212 as follows: from battery 233, winding 23 of electromagnet 212, switch spring 235 and contact, wire 236, armature and back contact of relay 312, upper armature and con tact of relay 307 .to ground, thus assuring that the plunger of the trunk finder will be retained in operated position. The lower armature completes a circuit from battery 308 through side switch wiper 346 and contact 350, vertical magnet 309,'private magnet relay 310, lower armature and front contact of 307, through resistance 311 to ground. 309 and 310 however are not energized due to the high resistance 311 in the circuit. The apparatus has now been prepared for the reception of the selective impulses which as before statcd are caused by interrupting the circuitat thesubstation.

Each interruption of the substation circuit will cause the denergization of relay 301, the armature of which upon retraction will short circuit the resistance311, causing .the energization of the vertical magnet 309 and relay 310. As these interruptions are of comparatively brief duration and follow each other in quick succession, the relays 307 and 310 being slow acting will not release during the intervals in which they are deprived of current. In accordance with the assumption that the substation to be selected was 99321, the first series of impulses would consist of ten interruptions of the substation circuit, causing the armature of relay 301 to be r tracted ten times, resulting in ten energiza tions of the vertical magnet 309, thus raising the set of brushes of the selector to the tenth level. In the first selector 101, here shown, the m ovable contact 313 is adapted to engage itsupper contact stop in all positions of the selector brushes except when positioned at the level in which the terminals individual to the satellite are located, or the tenth level in the case assumed. Thus the switch brushes having stopped in side switch the rotary magnet 31% will be substituted for the vertical magnet 309. The side switch is actuated by the private magnet 315 which upon energization of the relay 310 became energized by a circuit from battery, through contact 310, and armature of relay 310 to ground. The private magnet,

' however, does not eifect the movement of the side switch wipers upon encrgization,

but is adapted to move all of the wipers of the side switch one step upon deiinergization. The circuit of the private magnet is inter rupted when the armature of private magnet relay 310 falls back due to the prolonged inclusion of the resistance 311 in the circuit of relay 310 upon termination of the series of impulse The apparatus is now in position for the reception of the second series of impulses which in the case assumed would be ten. Upon the reception of this series of impulses the brushes of the selector wiil be stepped around to the tenth set of terminals in the tenth level which is the set individual to the satellite D. The brushes 317, 318 and 319 of the selector will now be on the contacts 320, 321 and 322. The circuit from the contacts 320 and 321 will be open and will have no function at this time.

The brush 319, however, completes through contact 322 a loop circuit which causes the energization of relay 312 over the following circuit: from the live pole of battery through winding of relay 315, contacts 310 and 351, contact 352, side switch wiper 326, brush 319 and contact 322, winding of relay 312, upper arn1ature and front contact of relay 307 to ground. The private magnet did not operate to move the side switch wipers to third position upon the termination of the ten thousands series of impulses as the contact 316 engaged contact 351 before ground was cut off at the armature of private magnet relay 310. Upon energization of relay 312 the high potential battery 327 is opposed to the battery 237 causing the polarized relay 238 to become energized over the following path: from ground through battery 327, front contact and armature of relay 312, wire 23G, contact and spring 235, winding of relay 238 and battery 237 to ground. Relay 238 has not been previously energized as the battery 237 was of the wrong polarity and as the current from battery 233, being of substantially the same potential as 237, was ineffective. The battery 327 may have a potential of 48 volts while the batteries 237 and 233 may each have a potential of 24 volts. Obviously, batteries of other potentials may be used if desired.

Upon the energization of relay 238 circuit aaaaasap; v

is momentarily icor'npleted fdrthe winding. 211 of relay 212- as follows: from battery" 213', through winding 211, armature 209 and upper. back contact through contact and armature of relay 238 to ground. This energizes the electromagnet 212" merely enough to attract the armature 221, thus completing a circuit for the windings 223" and 224 of electromagnet 212' from battery through normally closed contact 222 and lead 220", windings 223 and 224, contact and armature 221, lower back contact and armature 209, upper contact of armature 200, armature and contact of relay 238 to ground. Armatures 207, 208, 209' and 227' are thereupon attracted. Armature 227 causes the actuation of the plunger 217 of the satellite trunk finder 109, thus extending the sides 200, 201 of the subscribers line to the hundreds selector 403 of the satellite through the switch springs 205 and 206 respectively, and their coiiperating contacts.

The attraction of armatures 207, 208 interrupted'the circuit leading from the substation to the trunk finder 108 and thence to the selector 101 at the main exchange D. This causes the deencrgization of the line relay 301. When the armature of relay 301 is retracted, the circuit of relay 307 is in terrupi'cd which releases its lower armature completing a. circuit for the release magnet 328 frombattcry through said, magnet, oif

normal contact 329, back contact and lower armature of relay 307,-baclccontact and armature of relay 301 to ground. Thus the selector 101 is immediately returned to its normal condition and is again ready to be selected by a trunk finder.

Branching from the sides 200 and 201 of the line, as previously explained, are conductors leading to multipled contacts 239 and 240 of the connector switches through Y which the subscriber (1 would be reached when called. Associated with the contacts 230. and 240 is a test contact 2411. Upon the initiation of a call when the electromagnet 212 on the line finder 108 was en ergizech' and the armature 226 attracted, round was placed on the conductor leading h I to the test contact 241 so the multipled terminals of the calling subscribersflines wouldtcstbusy. Upon the deiincrgization of the clcctromagnet 212 by the interruption of the holding circuit for the winding 234 when the selector 101 returns to normal, as just explained, the armature 226 will be retracted, removing the ground at the front contact, but a ground through the back contact will be substituted there-for as will presently V be explained.

Upon the actuation of theplunger 217 ground-was placed on the lead 219 to the master. switch bank, whereby, as before described, the idle plungers of this group will be moved to a position in front of the contacts of an idle connecting circuit. By the actuation of the springs 205 and 206 ofthe trunk finder, the sides 200,- 201 respectively of the line are extended to-the hundreds selector 403 completing a circuit for the relay 400 as follows: battery, upper winding of relay 400, side 242 of the connecting circuit, contact and spring 205, side 200 of the line, substation apparatus, side 201 of the line, contact and spring 206, side 243 of the connecting circuit, lower winding ofrelay 400 to ground. Upon the energization of relay 400 a circuit is completed for relay 401 from battery through winding of 401, armature and front contact of 400, to ground. Upon the attraction of the upper armature of relay 401, ground is placed on the-test wire 244 of the connecting circuit. This serves to complete a circuit for the holding 423 and private magnet relay 424 to the back contact of relay 400. The hundreds selector 403 is now in condition to receive the next series of selective impulses.

As previously described, only so muchof the hundred selector and final connector. is" shown in Fig. 4 as is necessary to illustrate the principa signaling and talking circuits to the called subscribers station 0Z When the trunk finder made connection with the trunk line conductors 242, 243 and 244, the" relay 401 was energized and thus prepared the hundreds selector for operation in the well known manner by the impulses which subsequently occur. four impulses would now be sent and the In the case assumed brushes of the selector would be raised to the fourth level when they would automatically hunt for an idle connector. The en'- suing series of impulses (three and then two) would now cause the brushes ofthe' connector first to be stepped up to the third level in which are found the terminals of the called subscribers line, and then upon the final series of impulses, the brushes would be rotated until they were in engagement with the second set of contacts orthe line terminals of subscriber d Whenthej brushes made contact with theterininalsgf the called .subscribers' line, ground-; was

placed on the test conductor 423 through t e;

grounded contact of the side switch WiPQ FZ 130 425, thus assurmgthat no other connectors will stop on any of the multiple terminals of the line 0 Any well known method may be ernployed for signaling the called subscriber o and upon his response by lifting his re- 1 ing subscribers transmitter from battery 414 through the windings of relay 412, and to the called subscribers transmitter through the windings of relay 413, the talking circuit being interrupted to battery current between the connections of these relays to said conductor by condensers 409 and 411.

Upon the termination of the conversation, when the calling subscriber places his receiver upon the hook, the circuit for the relays 400 and'412 will be interrupted and the hundreds selector 403 and the connector 410 will then be returned to normal in the usual manner. e will now assume a call in which after the tenth level of the first selector 101 at the main exchange has been picked, a series of impulses other than ten are sent, thus stopping the brushes 317. 318, 319, for example, on contacts 330, 331, 332 respec- 35 tively. Upon the termination of this series switch contacts will be of impulses the side The line of the moved tothird position. calling subscriber will now be extended to one of the trunk finders 105. A circuit will now be completed for the winding 335 of the electromagnet of the line finder 105 from battery through said winding,v first lefthand armature and contact 336 tact 330, brush 317, 333, 304, 231, 229, 214, 207, 200, substation apparatus at d, 201, 208, 215, 230, 232, 305, 334, 318, 331, upper back contact and armature 342, to ground. The armature 341 is attracted and a local circuit is now completed for windings 337 and 338 from battei-y 339, through normally closed contact 340, windings 338, 337, contact and armature 3-l1, lower back contact and armature 342 to ground. The actuation of contact 343 serves to complete a holding circuit for the release magnet relay 307 thus holding open the circuit of release magnet The circuit for the relay 307 is as follows: live pole of battery through 307, 323, 324, 325,320,310, 332 to 343 and ground. Re-

0 la 307 is made slow uctln" and rouse uentlv did not release during the brief interval in which it was deprived of current. The euergization of windings 337 and 338 of electromagnet 330 causes theattraction of the right armature 344, thus actuating the thereof, conextending the line of the the brushes are stopped on any level but the tenth, contaci 313 would remain in engagement with the upper stop. Now upon termination of the first series of impulses, the side switch wipers will move to second position and a circuit will be completed from battery308 through wiper 340 and contact 34-7, through the winding of the rotary magnet 314, spring 313 and upper contact, through the winding of guarding relay 348 and interrupter 345) to ground. The brushes of the first selector would then automatically hunt for an idle second selector 102 (Fig. 1). When the test brush 319 engaged the test contact associated with an idle second selector, this contact would not be connected to ground and the private magnet 315 would be deprived of current, thus causing the side switch contacts 304, 305, 326 and 346 to step to the third position. Side switch wiper 34-0 in moving to the third position will remove battery from the rotary magnet 314- and thus stop the selector brushes in engagement with contacts associated with an idle second selector. The side switch 307, are, 324, ass. set, an), to ground at the second selector, thus retaining the release magnet relay energized. As the relay 307 is made slow acting, it did not release during the brief interval it was deprived of current. i

As the operation of setting up the connectio-n through the second selector 102, third selector 103 and final connector 104 would progress in the usual and well known manner, further description is thought to be unnecessary.

What is claimed is:

1. In an automatic telephone ext-"hange system, a main office, a satellite oliice, interotfice trunk lines extending from said satellite to said main office, local trunk lines within said satellite, means tor selecting an intcroliice trunk upon ill initiation of a call at said satellite. automati switching mechanism-tor efl'ecting connection between subin the usual manner to said satellite for governing said switching mechanism, and discriminating means at said main oiiice operated under the control of said controlling devices when manipulated in accordance with the number of the Wanted subscriber, for completing a connection over said interofiice trunk or for releasing said interoilice trunk and selecting a local trunk and eiiecting a connection over said local trunk according to whether the wanted subscriber is located at an exchange exterior to said satellite or at said satellite.

2. In a telephone exchange system, a main office, a satellite ofiice, trunk lines extending from said satellite to said main office and other trunk lines local to said satellite, a pair of trunk finders at said satellite, one for connecting the line of a calling subscriber at the satellite to an interoflice trunk and the other for connecting the line of the calling subscriber to a local trunk, and means at said main office whereby the interoiiice trunk finder is actuated upon the initiation of all calls at the satellite and whereby the local tr-unk finder is actuated only when the calling and called subscribers are at the same satellite.

3. In a tele hone exchange system, a main olfice, a satellite ofiice, trunk lines extendingfrom said satellite'to said main oihce and.

other trunk'lines local to said satellite, automatic switches for efiectmg connection between subscribers, a pair of trunk finders at said satellitethrough one of which talking connection is established from calling subscribers at the satellite to subscribers associated with the main ofiice and through the other of which connection is established, to

subscribers atsaid satellite, controlling dei so said mechanism a finders at said satell te for said interoflice,

vices associated with said satellite for governingsaid switches, and means'at said main -oifice operated under the control of said controlling devices when manipulated in accord ance with the number of a wanted subscriber for selecting the necessary line finder and completing a talking connection there- 4:. In a telephone exchange system, a main oflice, a satellite office, inte'roflice trunk lines extending between said satellite and said main oilice and local trunk lines at said satellite, automatic switching mechanism for effecting connection between subscribers, including a pair of trunk and local trunk lines-respectively, through calling subscriber may oneof which trunk finders the line of the be extended to subcliange and through scribers at the main '9 the other to subscribers trolling devices a.ssociate,d"" 'ith said satellite for governing said switches, andmeans at said main oflice operated. [a

of said controlling devicesvii 1163i,n'ianipn lated in accordance with the number of a der the control wanted subscriber for completing a, connection through the required one or the nism including a pair of trunk finders at said satellite through one of which the line of a calling subscriber at the satellite may be extended through switching mechanism to subscribers at said satellite and through the other of which said calling line may be extended by main oflice switching mechanism to subscribers external to the said satellite, and means at said main ofiice operating upon the initiation of a call at said satellite for automatically selecting and completing a connection through one or the other of said trunk finders according to whether the wanted subscriber is at the satellite or external thereto,

6. In a telephone exchange system, a main trunk finders and local trunk finders at said satellite and selectors at said main ofiice, one of said interofiice trunk finders being actuated upon the initiationofall calls 'at said satellite to select an inteioflice trunk to an idle selector, controlling devices for governing said switching mechanisms, said se lector operating under the control of a con trolling device at the satellite when manipulated in accordance with-the number of a Wanted subscriber at'said satellite to close a circuit, whereby means will be actuated to restore to normal said interoflice trunk finder and said selector, and complete atalk-v ing circuit between the calling and called subscribers through one of said local trunk finders.

7 t In a telephone exchange system, a main ofi'ice, a satelliteofiice, interoliice'trunk lines from said satellite to said main oflice and local trunk lines at said satellite, automatic switching mechanism for effecting connection between subscribers lines, said mechanism including local trunk finders and interoiiice trunk finders at said satellite and selectors at said main exchange, controlling; devices associatedwith said satellite forgot? erning the operation of said switches,

interoffic'e trunk finders being actuated uponf the initiation of all calls at theentellite I extend the line of the calling subscriber to a selector and said selector being actuated upon thereception of certain series of impulses from said controlling device to effect the operation of'mechanism, whereby the interoflice trunk will be released a'nd the local trunk finder will be operated to extend the line of the calling subscriber to one of said local trunks through said local trunk finder.

8. In a telephone exchange system, a main ofiice, a satellite oilice, trunk lines extending from said satellite to said main office and other trunk lines local to said satellite, automatic switching mechanism for extending a connection from a satellite subscriber to other subscribers at said exchange, said switching mechanism including interofiice trunk finders and local trunk finders at said satellite and selectors 21% said main exchange, governing sa1d I controlling devices or switching mechanism, an mtcroflice trunk finder being actuated upon initiation of allcalls at the satellite to select a trunk to an idle selector at the main exchange, 'said'first selector operating under the control of a controlling device when manipulated in accordance with the number of a wanted subscriber-at said satellite to close a circuit,

whereby means will be operated to restore to normal the interofiice trunk finder and complete a talking circuit between the calling and called subscribers through said local trunk finder.

9. In a telephone exchange s stem, a main oliice, a satellite office, intero ce trunk lines between said satellite and said main oflice and local trunk lines atsaid satellite, automatic switching mechanism for effecting connection between subscribers, said mechanism including interoffice trunk finders and local trunk finders at said satellite and selectors at the main office, electromagnets for operating said finders, a relay for completing an initial circuit for said local trunk finder electromagnet, means operating'upon energization of said local trunk finder clectrmnagnet to interrupt the connection between a calling line and said intei'oflice trunk finder, means for actuating one of said interollice trunk finders upon the initiation of a call at said satellite to select an interofiicc trunk to an idle selector, controlling deviccs for governing the movement of said switching mechanism, and

' means whereby said selectori operating undcr the control of a controlling device at the satellite when operated in accordance with the number of a wanted subscriber at said satellite will close a circuit for said relay.

10. In a telephone exchange system, a main oiiice, a second ofiice, interofiice trunk lines extending between said ofiices, other trunk lines local to said second .ofiice, and means at said main oilice whereby upon the the line of a calling subscriber thereat to an interofiice trunk and to a local trunk re- I 'spectively, and means at said main office whereby upon the initiation of all calls at said second office the subscribers line will be connected to an interofiice trunk and ,whereby the subscribers line will be connected to the local trunk only when the callmg and called subscribers are at said second oiiice.

12. In a telephone exchange s stem, a plurality of ofiices, subscribers l ines extending to said oflices, the designation of said lines being the same for all calling subscribers at the exchange, interofiice trunk lines extending between said oflices, local trunk lines at said oflices, an, individual line switch for each line for selecting an interoflice trunk upon the initiation of all calls at one office, switching mechanism for offecting connection between subscribers, controlling devices associated with said lines for governing said switching mechanism, a second individual switch for each line and means operated under the control of said controlling devices when manipulated in accordance-with the number of a wanted subscriber for completing a connection over said interofiice trunk or for releasing said interoiiice trunk and effecting a connection over said second individual switch and a local trunk according to whether the wanted subscriber is located at said first or second ofiice.

13. In a telephone exchange system, an oflice,'a second office, interoflice trunk lines extending between said ofiices, local trunk lines at said second ofiice, automatic switches for eflecting connection between subscribers, said switches including individual line switches through one of which the line of a calling subscriber at said second'ofiice may be extended to subscribers at the other oflice and through the other to subscribers at said second oflice, controlling devices associated with said second office for governing said switches, and means operated under the control of said controlling devices when manipulated 'n accordance with the number of the Wanted subscriber for completing a connection through the required one or the other of said line" switches according to whether the wanted subscriber is located at the first or second mentioned ofiice.

14. In a telephone exchange system, a group of lines, other lines a plurality oi switches vfor interconnecting the lines oi said group and a second plurality of switches for connecting the lines of said group to said other lines, controlling devices for governing the operation of said switches, means operated upon the initiation of a call at one of the lines of said grouplwhereby the controlling device thereof Willlbe associated with one of said second plurality of switches, said switch being operated under the control of such controlling device When manipulated in accordance with the number of a subscriber in said group of lines to 15 close a circuit whereby means Will be actuated to release said selected switch and complete a talking circuit between the calling and called lines through one of the first mentioned plurality of switches.

In witness whereof we hereunto subscribe our names this 7th day of May, A. D. 1913.

FRANK N. REEVES, ALBEN E. LUNDELL.

Witnesses:

WV. F. HOFFMAN, W. H. BROWN. 

